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# Clear Memory
rm(list=ls()) # WARNING: This deletes everything!!!!!


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##########  K-means Image Clustering ##########
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# Download image from the web

myurl <- "https://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/Earth_Western_Hemisphere.jpg/145px-Earth_Western_Hemisphere.jpg"
z <- tempfile()
download.file(myurl,z,mode="wb")

# Load package for reading jpeg image
library("jpeg")

image <- readJPEG(z)   # Read the image
file.remove(z)         # cleanup

# OR download image and load
# image <- readJPEG("image.jpg") 

# Obtain the dimension
image_Dim <- dim(image)
image_Dim

############## Data Formatting ################

# Create data frames and assign RGB vectors
RGB <- data.frame(
  x = rep(1:image_Dim[2], each = image_Dim[1]),
  y = rep(image_Dim[1]:1, image_Dim[2]),
  R = as.vector(image[,,1]),
  G = as.vector(image[,,2]),
  B = as.vector(image[,,3]))

############# Image Plotting Frame #################

# ggplot theme to be used
plotTheme <- function() {
  theme(
    panel.background = element_rect(size = 3, colour = "black",fill = "white"),
    axis.ticks = element_line(size = 3),
    panel.grid.major = element_line(colour = "gray90", linetype = "dashed"),
    panel.grid.minor = element_line(colour = "gray90", linetype = "dashed"),
    axis.title.x = element_text(size = rel(1.0), face = "bold"),
    axis.title.y = element_text(size = rel(1.0), face = "bold"),
    plot.title = element_text(size = 15, face = "bold",vjust = 1.0))
}

############# Plot Original Image #################
# Load package 
library("ggplot2")
#library("raster")

ggplot (data = RGB, aes(x = x, y = y)) + 
  geom_point(colour = rgb(RGB[c("R", "G", "B")])) +
  labs(title = "Original Image: Colorful Dragon") +
  xlab("x") + ylab("y") +
  plotTheme()

############# K-means Clustering #################

K_Clusters <- 4
kMeans <- kmeans(RGB[, c("R", "G", "B")], centers = K_Clusters)
kColours <- rgb(kMeans$centers[kMeans$cluster,])

############# Plot Clustered Image #################

ggplot (data = RGB, aes(x = x, y = y)) + 
  geom_point(colour = kColours) +
  labs(title = paste("k-Means Clustering of", K_Clusters, "Colours")) +
  xlab("x") + ylab("y") + 
  plotTheme()

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